Boring bar



May 12, 1942. E. A. ZIEMPEL 2,282,919

BORING BAR FiledDeC. 30, 1940 Inventar* '"EFLZEmpEl l Fittmr'nlig Patented May 12, 1942 azwsasia oFFlca BORING BAB Edward A. Zempel, Milwaukee, Wis.

Application'December 30, 1940, Serial No. 372,385

s claims. (c1. 'J7-58) This invention appertains to rotarycutting tools, and moreparticularly to boring'bars.

One of the primary objects of my invention is A to provide a novel tool carrier for boring bars, which can be readily and quickly associated with 'or removed from a boring bar, asa unit, without disturbing the ne micrometric adjustment of the cutting tool, whereby different units and tools of dierent characters (for roughing and nishing work) can be used with the same boring bar.

Another salient object of my invention is to provide a novel means for'mounting the cutting tool ir the -tool carrier, whereby the same' willbe effectively supported and held against turning movement, and whereby the desired micrometric adjustment of the cutting tool can be had inthe carrier.

Avfurther object of my invention is to provide novel` means for mounting thetool carrier in the boring bar, whereby the same ean'be rigidly' yclamped in place against accidental movement, and whereby chattering 'ofthecarrier and tool will beprevented,v irrespective ofthe length of time the vcarrier and bar are'used.

A further important object of my invention is to provide a detachable unit including the cutting. tool, carrier, adjusting mechanism for the tool, etc., which Vcanhe associated with boring bars unconventional formwith veryslight change thereto.

' A still further object ofmy invention is to pro-- wide a boring bar having a diametrically extending opening and cross slot at one side -communieatingV with one end of the opening,the rear face of the slot beingjormed straight, and the front face being formed with an-inclined surface, and a. detachable. unit including a tool l carrier having a barrel received in the openingand a crosshead tted in the slot, the rear face of the head being straight, and the .front face being formed'on an incline, with means for forcing the unit in the bar with the inclined faces of the head and slot in engagement for bringing the iiat faces of the head and slot in tight contact for carrying the load incident to the rotation -of Figure 3 looking in the direction of the arrows,

and illustrating the adjustment for the cutting ztool and the means for clamping the carrier of the umts in the boring bar.

Figure 2 is a fragmentary, side, elevational view of the forward end of the boring bar, with parts oi the bar broken,away and in'section to illustrate my detachable unit.

Figure 3 is a fragmentary top plan view oit-he 'front end oi the boring bar, constructed in accordance with my invention.

Figure 4 is a detail, sectional 'view taken on the line 4-4 of Figure 1,'looking in the direction of the arrows, illustrating the means for preventing turning movement of the cutting tool and the means for vclamping the cutting tool in its desired adjusted position.

Figure 5 is a front, elevational view of my novel unit removed from the boring bar. l

Figure 6 is 'an enlarged, detail, perspective view of the pin utilized `for holding the cutting tool against t movement.

Referring the drawing in detail, wherein 'similar reference characters designate correspndi'ng parts throughout the several views, the

- letter B indicates a boring` bar, and D my novel detachable unit therefor.'

In accordance with my invention, the boring bar B adjacent its iront end is provided with a diametricaily extending opening i0 and a cross slot H on one side communicating with one end of the opening. The rear wall l2 or the slot is formed straight, that is, at right angles to the longitudinal axis of the boring bar. 'I'he front face Il oi the slot is arranged on anincline and extends rearwardly and inwardly toward the axial center of thebar. f

Thus,` a conventional boring bar B can be utilized, and the same can be properly machined to iorlnl the opening III and my cross slot Il with its particular form. f

My detachable unit D includes a barrell Ii, which is adapted to be iltted within the opening Il, and one end of the barrel has formedthereon a crosshead It, which is adapted to ilt within4 the, slot Il. The inner face of the crosshead I6 is formed with a straight iiat surface l1, and

'fthe front face of the head is provided with a rearwardly and inwardly inclined f ce Il.v Th crosshead lits within the cross `alo and the straight face II of the head ilts against the straight rear wan lz' or the slot, while the 1nclined face IO of the crosshead ts against. the

inclined wall I S of the slot. l

The barrel ls has its bore la provided 'with an internal shoulder 2l at the end thereof, which is remote from the crosshead I6. Slidably mounted within the barrel I5 is the cutting tool 2l, and

this cutting tool protrudes through and beyond y,

the crosshead. The cutting tool can be formed from ,high-speed steel, or the same can be pro- 4vided with a Stellite tip or a tungsten carbide tool, and this internally threaded bore receives.

the threaded stem 23 of the micrometer adjusting screw 24. yThe head of the adjusting'screw.-

has formed thereon an. annular shoulder 25, which fits against the shoulder formed in the barrel. The shoulder 25 'is held .against the shoulder 20 by a fastening disc 26, and this fastening disc carries a split resilient ring 21,

4 which is adapted to snap into and out an internal groove formed in the bore of the barrel I5. The

.outer face of the head of the adjusting screw is calibrated, as at 28, andthe end of the barrel is provided withan indicating pointer or mark 29 for cooperation'with the scale'on the head of the screw. The head of the screw is provided with a `suitable tool-receiving socket, whereby said screw can be conveniently turned to adjust thecutting tool in and out.

In order to prevent the accidental turning of the cutting tool, the same is provided with a longitudinally extending guide slot 30, which receivesthe rib 3l formed on the inner end of a pin 32, which has a drive fit'within the crosshead.

After the cutting tool has been adjusted to the desired position,-the same is held against movement by a set screw 33, which is threaded in the crosshead I6 against one flat face of the cutting tool.

The outer face 'of the barrel I5 at right angles to the crosshead I6 is provided with a V-shaped groove 34, and an adjusting set screw is threaded into the boring bar, and the inner end of this adjusting set screw has formed thereon a conical tip 36, which is adapted to bear against the inner inclined wall of the groove 34.

When the detachable unit D isto be associated with the bar B, the adjusting set screw 35 is threaded out, and the unit D is slipped into the boring bar. The screw 35 is now turned inwardly until the conical tip thereof bears firmly against the inner inclined wall of the V-shaped groove -34. The conical tip bearing against the inclined wall forces the unit tight into the opening I0 and the cross slot II, with the inclined face I8 in engagement with the inclined wall I3 of the slot. This forces the straight face I1 of the crosshead into tight contact with the straight wall I2 of the slot, and these straight faces give a large bearing surface `for taking up strains and stresses incident to the turning of the boring bar. -Due to the torque set up, the greatest stress is against the at 4wall I2 of the cross slot, and as a large bearing surface is provided, the boring bar will effectively carry the stresses and strains.

In vall boring bars with which I am familiar, the tool bearing against the boring bar wears the boring bar away, and this allows the chattering of the tool, and where undue play is present the tool sometimes is snapped off.

With myV novel arrangement and formation of parts, the entire, unit D with the cutting tool can be instantly removed from the boring bar by the mere loosening of the adjusting screw 35. This allows the convenient re-sharpening of the cutting tool without disturbing the fine adjustment of the cutting tool', and as the unit can be freely removed from the bar, I can provide several units.

for one bar, that is, I can provide one unit with acutting tool for rou-ghing and another unit with a cutting tool for finishing, and I am permitted to maintain accuracy in adjustment to givethe exact size to the work being operated upon.

The setscrew 33 not only functions to clamp the "cutting tool in the carrier, but also limits the outward adjustment of the cutting tool, and this prevents the accidental turning out of the adjusting screw 24 from the cuttingtool.

From the foregoing description it can be seen that I have provided an exceptionally simple and durable unit for boring bars, or the like.

In some instances, it may have been desirable t to employ a master bar, and setting gauge to allow setting of the cutter to desired cutting size away from the bar and machine.

Changes in details may be made without departing from the spirit or the scope of my invention, but what I claim as new is:-Y

1.A boring tool comprising, a bar having an opening therein and a cross slot on one side communicating with the opening, and a detachable unit for association with the bar including a carrier having a barrel fitted in the opening and a crosshead integral therewith fitted in the slot, a cutting tool slidably mounted in the barrel and extending outward beyond the crosshead, means for adjusting the cutting tool in the barrel, and

means for detachably and firmly clamping the unit in the bar.

2. A boring tool comprising, a bar having an opening therein and a cross slot on one side communicating with said opening, said cross slot having an inner flat fac-e, a detachable unit removably associated with the bar including a carrier havinga barrel fitted in the opening and a crosshead integral therewith fitted in the slot, the inner wall of the crosshead having a smooth flat surface for intimate contact with the fiatv wall of the groove, means detachably clamping the carrier in the bar and for forcing the flat surface of the head into intimate contact with the flat wall of the groove, a cutting tool slidably mounted in the barrel and extending outwardly beyond the crosshead, and means for adjusting the cutting tool in the barrel.

3. A boring tool comprising, a barrel having an opening and a cross slot on one side communicating with the opening, the inner wall of. the cross slot being formed straight, the forward wall of the cross slot being on an incline and extending rearwardly and inwardly, a detachable unit for association with the bar including a carrier having a barrel detachably fitted in the opening and a crosshead integral therewith fitted in the slot, the rear surface of the crosshead being formed fiat, the front surface of the crosshead being on an incline and extending rearwardly and inwardly for engaging the inclined front wall of the slot, a cutting tool slidably mounted in the barrel, means for adjusting the tool in said barrel, and means for firmly clamping the carrier in the bar and for drawing the inclined surface of the head in engagement with vthe inclined wall of the cross slot, whereby the straight surface of the crosshead will be brought into intimate bearing contact with the straight wall of the slot.

brought into intimate bearing contact aannamel r`i?.

4. A boring tool comprising, a vbarrel having an opening and a cross slot on one Aside communicating with the opening, the inner wall of the cross slot being fon'ned straight, the forward wall oi' the cross'slot being on an incline and 5 extending rearwardly and inwardly, a detachable A unit for association with the bar including a carrier having a barrel detachably fitted in thel opening and a crosshead integral therewith ntted in the slot, the rear surface of the cross- 10 head being formed nat, the iront surface of the crosshead being on an incline and extending rearwardly and inwardly for engaging the inn clined irot wall of the slot, a cutting tool slidably mounted in the Lbarrel, means for adjust- 15 including a V-shaped groove on one side ofthe barrel and an adjusting set screw'threaded into the bar having a pointed tip for contact with the 25 inner inclined wall of the V-shaped groove.

`5. A boring tool comprising, a boring bar having an opening therein and a cross slot onone bead side communicating with oneA the opening. a unit removably associated withthe bar includiing bmel nttedyithm the opening andava-oss'- l head integral therewith fitted in Vthe-slot, means l for detachably securing the unit in the ban-a cutting tool slidablv mounted in theV barrel, and means carried wholly by thebarrelfor adjusting the cutting tool. A.

6. A removable unit for boring bars comprisi ing. a carrier including a barrel and an integral crosshead, the barrel-having airinterirtal shoulder at one end, a cutting tool mounted in the barrel having a liiat surfacejon o'ne side` and a longitudinally extending-'groove on the other, means carried by the tting in the groove forl preventing rotation of the'feutting tool,

a set screw carried by the carrierlfor' the nat surface 6i' the cuttingl tool for lholding the same in an adjusted positiomfsaid screw also limiting the outward movement of the tool in the'barrel, an adjusting screw having a shoulder on its head fitted against the shoulder in the barrel, means rotatably supporting the set screw in the barrel, and saidcutting tool having an internally threaded bore `for receiving the stem ofthe adjusting screw. v

A Enwann Ala.. 

